The present disclosure relates generally to the field of vehicular travel and more particularly to a video system which informs one or more passengers seated in an enclosed windowless suite in a vehicle of the vehicle's attitude and changes in vehicle attitude (e.g. pitching nose up or nose down, or yawing or rolling to the right or left). Such windowless suites are now found in luxury long haul aircraft cabin suites of commercial aircraft.
It has long been known that airline passengers seated in window seats report experiencing higher comfort levels than passengers in other cabin areas. See U.S. Pat. No. 5,611,503, particularly FIG. 4. While there may be several reasons for this higher reported comfort level, psychological studies have shown that enabling passengers to be correctly oriented in space is an important contributor to passenger comfort. While some passengers experience acute motion sickness when deprived of visual references informing them of changes in vehicle attitude, a majority of airline passengers experience only a somewhat diminished comfort, the origin of which is unknown to them, when experiencing properly-coordinated maneuvers of a commercial airplane without a visual reference informing them of changes in airplane attitude.
Forward looking and downward looking “landscape” cameras displaying images on a video screen generally forward of the passenger are well known. Static airplane mockups incorporating video screens in lieu of actual windows are also known. In this and similar known applications, a single image has been replicated on all screens on the same side of the mockup.
Forward looking landscape cameras do not provide a reliable attitude reference during takeoff maneuvers because the nose of the aircraft is quickly pointed skyward, leaving no observable horizon. As a result, the disappearance of the horizon as the airplane rotates on takeoff can be disorienting to passengers. Downward looking cameras also do not provide an intuitive attitude reference to the passengers. Furthermore, the video screen displaying these images serves a variety of information and entertainment purposes and is rarely turned to the camera mode, rendering it unlikely to relieve motion-oriented discomfort resulting from a cause unrecognized by the passenger.
While they have been used in static mockups in which motion oriented discomfort is not an issue, emulating a row of aircraft windows with video monitors has never been considered sufficiently attractive for use in an airplane to justify developing and flight testing such a system. For a typical airplane cabin with many occupants and many monitors emulating actual windows, no viable alternative has been found to repeating the same image on each monitor down the length of a side of the cabin. When an airplane is climbing, repeating the same image in each monitor along a row of windows presents the image of a level flight over a sawtooth landscape. Any such perceived attitude reference is ambiguous or confusing. When an airplane is rolling, monitors farther from the passenger subtend a smaller vertical field of view. Accordingly, to each individual passenger the rear of the airplane will appear to be rolling more quickly than the front of the airplane; an appearance more likely to induce motion sickness than alleviate it.
Image latency presents the hazard of causing motion sickness when the feeling of motion provided by the passenger's sense of equilibrium is out of sync with the motion seen in virtual windows—as when their vestibular system senses an aircraft maneuver while their visual system still senses level flight (and vice versa).